Compact printer with capping mechanism

ABSTRACT

A compact printer has a powered roller for moving printable media past a fixed printhead. A nozzle capping mechanism for the printhead includes a capping arm operatively associated with the powered roller, a cap supported by the capping arm and movable with the capping arm between a position protecting the printhead and a position spaced from the printhead. The cap rests adjacent the printhead with the capping arm moving the cap away from the printhead when the powered roller rotates.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.09/575,182 filed May 23, 2000, the entire contents of which are hereinincorporated by reference.

FIELD OF THE INVENTION

The invention relates to a compact printer system able to printfull-color, business card size documents from a device about the size ofa pen. The system includes various hot-connectable modules that providea range of functions. In particular the invention relates to a compactcolor printer that provides a print function for the compact printersystem.

Reference may be had to co-pending applications claiming priority fromAustralian Provisional Patent Application number PQ0560 dated 25 May1999. The co-pending applications describe related modules and methodsfor implementing the compact printer system. The co-pending applicationsare as follows: USSN Title 09/575,173 Modular Compact Printer System6,416,160 Nozzle Capping Mechanism 6,238,043 Ink Cartridge for CompactPrinter System 09/575,119 Controller for Printer Module 09/575,135Camera Module for Compact Printer System 09/575,157 Image Processor forCamera Module 6,554,459 Memory Module for Compact Printer System09/575,134 Effects Module for Compact Printer System 09/575,121 EffectsProcessor for Effects Module 09/575,137 Timer Module for Compact PrinterSystem 09/575,167 Color Conversion Method for Compact Printer System09/575,120 Method and Apparatus of Dithering 09/575,122 Method andApparatus of Image Conversion

BACKGROUND OF THE INVENTION

Microelectronic manufacturing techniques have led to the miniaturizationof numerous devices. Mobile phones, personal digital assistant devices,and digital cameras are very common examples of the miniaturizationtrend.

One device that has not seen the advantage of microelectronicmanufacturing techniques is the printer. Commercially available printersare large compared to many of the devices they could support. Forinstance, it is impractical to carry a color printer for the purpose ofinstantly printing photographs taken with known compact digital cameras.

A compact printhead has been described in co-pending United StatesPatent Applications filed simultaneously to the present application andhereby incorporated by cross reference: USSN Title 09/575,152 Fluidicseal for an ink jet nozzle assembly 6,428,133 Ink jet printhead having amoving nozzle with an externally arranged actuator 6,526,658 Method ofmanufacture of an ink jet printhead having a moving nozzle with anexternally arranged actuator 6,328,417 Ink jet printhead nozzle array6,390,591 Nozzle guard for an ink jet printhead

SUMMARY OF THE INVENTION

In one form, the invention resides in a printer module for a compactprinter system comprising:

-   -   an elongate body;    -   a stationary printhead housed within said body,    -   means for moving a printable media past said stationary        printhead;    -   an ink reservoir within said body and communicating with said        printhead;    -   means within said body for storing an image to be printed by        said printhead; and    -   means for transferring said image to said printhead;    -   said printhead printing said image on substantially the full        width of said printable media in a single pass.

Further features of the invention will be evident from the followingdescription.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to assist with describing preferred embodiments of theinvention, reference will be made to the following figures in which:

FIG. 1 is a printer module;

FIG. 2 is a camera module;

FIG. 3 is a memory module;

FIG. 4 is a communication module;

FIG. 5 is a flash module;

FIG. 6 is a timer module;

FIG. 7 is a laser module;

FIG. 8 is an effects module;

FIG. 9 is a characters module;

FIG. 10 is an adaptor module;

FIG. 11 is a pen module;

FIG. 12 is a dispenser module;

FIG. 13 is a first compact printer configuration;

FIG. 14 is a second compact printer configuration;

FIG. 15 is a third compact printer configuration;

FIG. 16 is a fourth compact printer configuration;

FIG. 17 is an exploded view of the Printer Module of FIG. 1;

FIG. 18 is a top view of the Printer Module with ink cartridge removed;

FIG. 19 is a cross-sectional view through AA in FIG. 18; and

FIG. 20 is a block circuit diagram of a controller for the printermodule.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1 to 12, there are shown various modules thattogether form a compact printer system. Individual modules can beattached and detached from the compact printer configuration to allow auser-definable solution to business-card sized printing. Images can alsobe transferred from one compact printer to another without the use of asecondary computer system. Modules have a minimal user-interface toallow straightforward interaction.

A compact printer system configuration consists of a number of compactprinter modules connected together. Each compact printer module has afunction that contributes to the overall functionality of the particularcompact printer configuration. Each compact printer module is typicallyshaped like part of a pen, physically connecting with other compactprinter modules to form the complete pen-shaped device. The length ofthe compact printer device depends on the number and type of compactprinter modules connected. The functionality of a compact printerconfiguration depends on the compact printer modules in the givenconfiguration.

The compact printer modules connect both physically and logically. Thephysical connection allows modules to be connected in any order, and thelogical connection is taken care of by the compact printer Serial Bus—abus that provides power, allows the modules to self configure andprovides for the transfer of data.

In terms of physical connection, most compact printer modules consist ofa central body, a male connector at one end, and a female connector atthe other. Since most modules have both a male and female connector, themodules can typically be connected in any order. Certain modules onlyhave a male or a female connector, but this is determined by thefunction of the module. Adaptor modules allow these single-connectormodules to be connected at either end of a given compact printerconfiguration. The modules connect such that the bodies of two adjacentmodules abut each other, thereby maintaining a rigid unit for greaterease of operation.

A four wire physical connection between all the compact printer modulesprovides the logical connection between them in the form of the compactprinter Serial Bus. The compact printer Serial Bus provides power toeach module, and provides the means by which data is transferred betweenmodules. Importantly, the compact printer Serial Bus and accompanyingprotocol provides the means by which the compact printer systemauto-configures, reducing the user-interface burden on the end-user.

Compact printer modules can be grouped into three types:

-   -   image processing modules including a Printer Module (FIG. 1), a        Camera Module (FIG. 2), and a Memory Module (FIG. 3). Image        processing modules are primarily what sets the compact printer        system apart from other pen-like devices. Image processing        modules capture, print, store or manipulate photographic images;    -   housekeeping modules including an Adapter Module (FIG. 10), an        Effects Module (FIG. 8), a Communications Module (FIG. 4), and a        Timer Module (FIG. 6). Housekeeping modules provide services to        other modules or extended functionality to other modules; and    -   isolated modules including a Pen Module (FIG. 11) and a Laser        Module (FIG. 7). Isolated modules are those that attach to the        compact printer system but are completely independent of any        other module. They do not necessarily require power, and may        even provide their own power. Isolated Modules are defined        because the functionality they provide is typically incorporated        into other pen-like devices.

Although housekeeping modules and isolated modules are useful componentsin a compact printer system, they are extras in a system dedicated toimage processing and photographic manipulation. Life size (1:1)illustrations of the compact printer modules are shown in FIGS. 1 to 12,and example configurations produced by connecting various modulestogether are shown in FIGS. 13 to 16.

FIG. 1 shows a printer module that incorporates a compact printheaddescribed in co-pending U.S. patent applications listed in theBackground section of this application, incorporated herewith byreference, and referred to herewith as a Memjet printhead. The Memjetprinthead is a drop-on-demand 1600 dpi inkjet printer that producesbi-level dots in up to 4 colors to produce a printed page of aparticular width. Since the printhead prints dots at 1600 dpi, each dotis approximately 22.5 μm in diameter, and spaced 15.875 μm apart.Because the printing is bi-level, the input image should be dithered orerror-diffused for best results. Typically a Memjet printhead for aparticular application is page-width. This enables the printhead to bestationary and allows the paper to move past the printhead. A Memjetprinthead is composed of a number of identical ½ inch Memjet segments.

The printer module 10 comprises a body 11 housing the Memjet printhead.Power is supplied by a three volt battery housed in battery compartment12. The printhead is activated to commence printing when a business card(or similar sized printable media) is inserted into slot 13. Maleconnector 14 and female connector 15 facilitate connection of othermodules to the printer module 10.

FIG. 2 shows a camera module 20. The camera module provides apoint-and-shoot camera component to the compact printer system as ameans of capturing images. The camera module comprises a body 21 havinga female connector 22. A lens 23 directs an image to an image sensor andspecialized image processing chip within the camera 24. A conventionalview finder 25 is provided as well as a lens cap 26. An image iscaptured when the Take button 27 is pushed. Captured images aretransferred to the Printer Module 10 for subsequent printing,manipulation, or storage. The Camera Module also contains a self-timermode similar to that found on regular cameras.

FIG. 3 shows a Memory Module 30 comprising a body 31, LCD 32, IN button33, OUT button 34 and SELECT button 35. The Memory Module 30 is astandard module used for storing photographic images captured by theCamera 20. The memory module stores 48 images, each of which can beaccessed either at full resolution or at thumbnail resolution. Fullresolution provides read and write access to individual images, andthumbnail resolution provides read access to 16 images at once inthumbnail form.

The Memory Module 30 attaches to other modules via a female connector 36or male connector 37. The male and female connectors allow the module tobe connected at either end of a configuration. Power is provided fromthe Printer Module 10 via the Serial Bus.

A Communications Module 40 is shown in FIG. 4. The communications module40 consists of a connector 41 and a cable 42 that terminates in anappropriate connector for a computer port, such as a USB port, RS232serial port or parallel port. The Communications Module 40 allows thecompact printer system to be connected to a computer. When so connected,images can be transferred between the computer and the various modulesof the compact printer system. The communications module allows capturedimages to be downloaded to the computer, and new images for printing tobe uploaded into the printer module 10.

A Flash Module 50 is shown in FIG. 5. The Flash Module 50 is used togenerate a flash with flash cell 51 when taking photographs with theCamera Module 20. The Flash Module attaches to other modules via femaleconnector 52 and male connector 53. It contains its own power source.The Flash Module is automatically selected by the Camera Module whenrequired. A simple switch allows the Flash Module to be explicitlyturned off to maximize battery life.

FIG. 6 shows a Timer Module 60 that is used to automate the taking ofmultiple photos with the Camera Module 20, each photo separated by aspecific time interval. The captured photos are stored in Memory Module30. Any flash requirements are handled by the Camera Module 20, and cantherefore be ignored by the Timer Module. The Timer Module 60 consistsof a body 61 housing a LCD 62, START/STOP button 63 and UNITS button 64.A SELECT button 65 allows the user to select time units and the numberof units are set by UNITS button 64. The Timer Module 60 includes a maleconnector 66 and female connector 67. The Timer Module takes its powerfrom the Printer Module 10 via the Serial Bus.

A Laser Module 70 is shown in FIG. 7. The Laser Module 70 consists of abody 71 containing a conventional laser pointer operated by button 72.As the Laser Module is a terminal module it only has one connector,which in the example is a male connector 73. The Laser Module is anisolated module, in that it does not perform any image capture, storage,or processing. It exists as a functional addition to the compact printersystem. It is provided because laser pointer services are typicallyincorporated into other pen-like devices. The Laser Module contains itsown power supply and does not appear as a device on the Serial Bus.

The Effects Module shown in FIG. 8 is an image processing module. Itallows a user to select a number of effects and applies them to thecurrent image stored in the Printer Module 10. The effects includeborders, clip-art, captions, warps, color changes, and painting styles.The Effects Module comprises a body 81 housing custom electronics and aLCD 82. A CHOOSE button 83 allows a user to choose between a number ofdifferent types of effects. A SELECT button 84 allows the user to selectone effect from the number of effects of the chosen type. Pressing theAPPLY button 85 applies the effect to image stored in the Printer Module10. The Effects Module obtains power from the Serial Bus. Male connector86 and female connector 87 allow the Effects Module to be connected toother compact printer system modules.

FIG. 9 shows a Character Module 90 that is a special type of EffectsModule (described above) that only contains character clip-art effectsof a given topic or genre. Examples include The Simpsons®, Star Wars®,Batman®, and Dilbert® as well as company specific modules for McDonalds®etc. As such it is an image processing module. It consists of a body 91housing custom electronics and a LCD 92. SELECT button 93 allows theuser to choose the effect that is to be applied with APPLY button 94.The Character Module obtains power from the Serial Bus through maleconnector 95 and female connector 96.

The Adaptor Module 100, shown in FIG. 10, is a female/female connectorthat allows connection between two modules that terminate in maleconnectors. A male/male connector (not shown) allows connection betweentwo modules that terminate in female connectors. The Adaptor Module is ahousekeeping module, in that it facilitates the use of other modules,and does not perform any specific processing of its own.

All “through” modules have a male connector at one end, and a femaleconnector at the other end. The modules can therefore be chainedtogether, with each module connected at either end of the chain. Howeversome modules, such as the Laser Module 70, are terminating modules, andtherefore have either a male or female connector only. Suchsingle-connector modules can only be connected at one end of the chain.If two such modules are to be connected at the one time, an AdaptorModule 100 is required.

FIG. 11 shows a Pen Module 110 which is a pen in a module form. It is anisolated module in that it attaches to the compact printer system but iscompletely independent of any other module. It does not consume orrequire any power. The Pen Module is defined because it is a convenientextension of a pen shaped, pen sized device. It may also come with a cap111. The cap may be used to keep terminating connectors clean in thecase where the chain ends with a connector rather than a terminatingmodule.

To assist with accurately feeding a business card sized print media intoslot 13 of the printer module 10, a dispenser module 120 is provided asshown in FIG. 12. The dispenser module 120 comprises a body 121 thatholds a store of business card sized print media. A Printer Module 10locates into socket 122 on the dispenser module 120. When correctlyaligned, a card dispensed from the dispenser module by slider 123 entersslot 13 and is printed.

In the sense that a minimum configuration compact printer system must beable to print out photos, a minimum compact printer configurationcontains at least a Printer Module 10. The Printer Module holds a singlephotographic image that can be printed out via its Memjet printer. Italso contains the 3V battery required to power the compact printersystem.

In this minimum configuration, the user is only able to print outphotos. Each time a user inserts a business card 130 into the slot inthe Printer Module, the image in the Printer Module is printed onto thecard. The same image is printed each time a business card is insertedinto the printer. In this minimum configuration there is no way for auser to change the image that is printed. The dispenser module 120 canbe used to feed cards 130 into the Printer Module with a minimum offuss, as shown in FIG. 13.

By connecting a Camera Module 20 to the minimum configuration compactprinter system the user now has an instant printing digital camera in apen, as shown in FIG. 14. The Camera Module 20 provides the mechanismfor capturing images and the Printer Module 10 provides the mechanismfor printing them out. The battery in the Printer Module provides powerfor both the camera and the printer.

When the user presses the “Take” button 27 on the Camera Module 20, theimage is captured by the camera 24 and transferred to the Printer Module10. Each time a business card is inserted into the printer the capturedimage is printed out. If the user presses “Take” on the Camera Moduleagain, the old image in the Printer Module is replaced by the new image.

If the Camera Module is subsequently detached from the compact printersystem, the captured image remains in the Printer Module, and can beprinted out as many times as desired. The Camera Module is simply thereto capture images to be placed in the Printer Module.

FIG. 15 shows a further configuration in which a Memory Module 30 isconnected to the configuration of FIG. 14. In the embodiment of FIG. 15,the user has the ability to transfer images between the Printer Module10 and a storage area contained in the Memory Module 30. The userselects the image number on the Memory Module, and then either sendsthat image to the Printer Module (replacing whatever image was alreadystored there), or brings the current image from the Printer Module tothe specified image number in the Memory Module. The Memory Module alsoprovides a way of sending sets of thumbnail images to the PrinterModule.

Multiple Memory Modules can be included in a given system, extending thenumber of images that can be stored. A given Memory Module can bedisconnected from one compact printer system and connected to anotherfor subsequent image printing.

With the Camera Module 20 attached to a Memory Module/Printer Modulecompact printer system, as shown in FIG. 15, the user can “Take” animage with the Camera Module, then transfer it to the specified imagenumber in the Memory Module. The captured images can then be printed outin any order.

By connecting a Communications Module 40 to the minimum configurationcompact printer system, the user gains the ability to transfer imagesbetween a PC and the compact printer system. FIG. 16 shows theconfiguration of FIG. 15 with the addition of a Communications Module40. The Communications Module makes the Printer Module 10 and any MemoryModules 30 visible to an external computer system. This allows thedownload or uploading of images. The communications module also allowscomputer control of any connected compact printer modules, such as theCamera Module 20.

In the general case, the Printer Module holds the “current” image, andthe other modules function with respect to this central repository ofthe current image. The Printer Module is therefore the central locationfor image interchange in the compact printer system, and the PrinterModule provides a service to other modules as specified by userinteraction.

A given module may act as an image source. It therefore has the abilityto transfer an image to the Printer Module. A different module may actas an image store. It therefore has the ability to read the image fromthe Printer Module. Some modules act as both image store and imagesource. These modules can both read images from and write images to thePrinter Module's current image.

The standard image type has a single conceptual definition. The imagedefinition is derived from the physical attributes of the printhead usedin the Printer Module. The printhead is 2 inches wide and prints at 1600dpi in cyan, magenta and yellow bi-level dots. Consequently a printedimage from the compact printer system is 3200 bi-level dots wide.

The compact printer system prints on business card sized pages (85 mm×55mm). Since the printhead is 2 inches wide, the business cards areprinted such that 1 line of dots is 2 inches. 2 inches is 50.8 mm,leaving a 2 mm edge on a standard business-card sized page. The lengthof the image is derived from the same card size with a 2 mm edge.Consequently the printed image length is 81 mm, which equals 5100 1600dpi dots. The printed area of a page is therefore 81 mm×51 mm, or5100×3200 dots.

To obtain an integral contone to bi-level ratio a contone resolution of267 ppi (pixels per inch) is chosen. This yields a contone CMY page sizeof 850×534, and a contone to bi-level ratio of 1:6 in each dimension.This ratio of 1:6 provides no perceived loss of quality since the outputimage is bi-level.

The printhead prints dots in cyan, magenta, and yellow ink. The finaloutput to the printed page must therefore be in the gamut of theprinthead and take the attributes of the inks into account. It would atfirst seem reasonable to use the CMY color space to represent images.However, the printer's CMY color space does not have a linear response.This is definitely true of pigmented inks, and partially true fordye-based inks. The individual color profile of a particular device(input and output) can vary considerably. Image capture devices (such asdigital cameras) typically work in RGB (red green blue) color space, andeach sensor will have its own color response characteristics.

Consequently, to allow for accurate conversion, as well as to allow forfuture image sensors, inks, and printers, the CIE L*a*b* color model[CIE, 1986, CIE 15.2 Colorimetry: Technical Report (2^(nd) Edition),Commission Internationale De l'Eclairage] is used for the compactprinter system. L*a*b* is well defined, perceptually linear, and is asuperset of other traditional color spaces (such as CMY, RGB, and HSV).

The Printer Module must therefore be capable of converting L*a*b* imagesto the particular peculiarities of its CMY color space. However, sincethe compact printer system allows for connectivity to PCs, it is quitereasonable to also allow highly accurate color matching between screenand printer to be performed on the PC. However the printer driver or PCprogram must output L*a*b*.

Each pixel of a compact printer image is therefore represented by 24bits: 8 bits each of L*, a*, and b*. The total image size is therefore1,361,700 bytes (850×534×3).

Each image processing module is able to access the image stored in thePrinter Module. The access is either to read the image from the PrinterModule, or to write a new image to the Printer Module.

The communications protocol for image access to the Printer Moduleprovides a choice of internal image organization. Images can be accessedeither as 850×534 or as 534×850. They can also be accessed ininterleaved or planar format. When accessed as interleaved, each pixelin the image is read or written as 24 bits: 8 bits each of L*, a*, b*.When accessed as planar, each of the color planes can be read or writtenindependently. The entire image of L* pixels, a* pixels or b* pixels canbe read or written at a time.

Detailed views of the Printer Module 10 are shown in FIGS. 17, 18 and19. The Printer Module 10 is the central module in the compact printersystem. It contains a 2-inch Memjet printhead 16, a Cyan/Magenta/Yellowink cartridge 17, the current image stored in flash memory on theprinthead, and a power source in the form of a 3V battery 12 a in thebattery compartment 12. With regards to processing, the Printer Module10 contains a controller chip (or chips) 101 that controls printing ofthe stored image in high quality.

The Printer Module 10 can be used as a stand-alone printer of a singleimage (such as business cards), or can be used in conjunction with othermodules to print a variety of images.

Looking in detail at FIG. 17, the body 11 of the printer module is inthree parts being a lid 11 a, base 11 b and chassis 11 c. Printhead 16with filter 16 a fits into the chassis 11 c. Powered rollers 18 a aredriven by motor and gearbox 103. Neutral rollers 18 b fit into inkcartridge 17 and guide a card past the printhead 16. Springs 18 c (FIG.19) urge the neutral rollers 18 b towards the powered rollers 18 a. Theink cartridge 17 is located beyond the rollers 18 so that the cardpasses between the printhead 16 and the ink cartridge 17. Ink inlets 105provide communication between the ink cartridge 17 and the printhead 16.Micro-moulded channels 106 in the chassis 11 c distribute the ink fromthe ink inlets 105 to the length of the printhead 16.

Serial bus 104 provides power and data between the printer module 10 andother modules connected to male connector 14 and female connector 15.The serial bus 104 picks up power from the battery 12 a and signals fromthe controller 101. Looking at FIG. 19, to print an image, a user simplyinserts a business card into the input slot 13 of the Printer Module.Sensor 102 detects the insertion and a small motor 103 a and gearbox 103b activates rollers 18 to carry the card through the module. A tab film107 provides signal connection from the sensor 102 to the controller 101and hence to the motor and gearbox 103. A wedge 108 holds the tab film107 in place to make a signal connection.

The printed card is ejected from the output slot 13 a of the module overa time period of 1 second. There is no on/off switch—the act ofinserting the card is the effective “on” switch for the duration of aprint.

To reduce the chance of ink drying in the printhead 16 a cappingmechanism 19 is provided to cap the ink nozzles in the printhead. Thecapping mechanism 19 comprises a capping arm 191 supporting a blotter192 with adjacent elastomeric seals 193. A clutch 194 is operativelyassociated with one of the powered rollers 18 a to move the capping arm191 out of the path of the card for printing.

The volume of ink present in an ink cartridge is 450 ml (2 mm×3 mm×75mm), enough to produce 450 million dots of a given color. The exactnumber of images that can be printed before replacement will depend onthe color composition of those images. 450 ml represents:

-   -   25 full black cards (black requires all three colors to be used)    -   50 full sized photos at 50% CMY coverage    -   111 typical photo/text cards at 22.5% CMY coverage    -   166 cards of black (CMY) text at 15% coverage

A QA chip in the ink cartridge keeps track of how much ink has beenused. Sensors in the ink cartridge provide signals to the QA chip thatare transferred to the controller 101 via contacts 109. If there isinsufficient ink of any color to print a given image, the card will passthrough the printer module, but nothing will be printed.

It is a simple matter to replace the old ink cartridge 17 by slidinglatch 171, removing lid 11 a, unclipping the old cartridge and clippingon a new one.

A schematic of a suitable controller 101 is shown in FIG. 20. Thecontroller may be embodied in a single application specific integratedcircuit or in a number of discrete elements. The controller 101 includesa simple micro-controller CPU core 201 with associated program ROM 202and program RAM 203. The CPU 201 communicates with the other unitswithin the controller via memory-mapped I/O supported by a MemoryDecoder 204. The Decoder 204 translates data addresses into internalcontroller register accesses over the internal low speed bus 205, andtherefore allows for memory mapped I/O of controller registers. The bus205 includes address lines 205 a and data or control lines 205 b.

An optional Serial Bus interface 206, is connected to the internal chiplow-speed bus 205 and connects to the Serial Bus for communication withother modules. A parallel interface 207 provides communication to themotor and gearbox 103 in the printer module 10. It can also receivesignals from buttons, such as a paper sensor 102.

There are two optional low-speed serial interfaces 208, 209 connected tothe internal low-speed bus 205. A first interface 208 connects to the QAchip 220 in the ink cartridge of the printer module 10. The secondinterface connects to a QA chip 221 on the print module 10. The reasonfor having two interfaces is to connect to both the on-module QA Chip221 and to the ink cartridge QA Chip 220 using separate lines to improvesecurity. If only a single line is used, a clone ink cartridgemanufacturer could usurp the authentication mechanism and provide anon-proprietary cartridge.

The total amount of memory required for the interleaved linearCMY/L*a*b* image is 1,361,700 bytes (approximately 1.3 MB). The image iswritten to Image Storage Memory 211 by the Image Access Unit 212, andread by both the Image Access Unit 212 and the Printhead Interface (PHI)210. The CPU does not have direct random access to this image memory. Itmust access the image pixels via the Image Access Unit 212. ThePrinthead Interface 210 is the means by which the controller loads theprinthead 16 with the dots to be printed, and controls the actual dotprinting process.

The controller 101 may also include a clock phase-locked loop 213 thatprovides timing signals to the controller. The clock 213 draws a basesignal from crystal oscillator 214. Some CPU include a clock so theclock and crystal would not be required.

A standard JTAG (Joint Test Action Group) Interface 215 is included inthe controller for testing purposes. Due to the complexity of thecontroller, a variety of testing techniques are required, including BIST(Built In Self Test) and functional block isolation. An overhead of 10%in chip area is assumed for overall chip testing circuitry.

The battery used to power the compact printer system is a CR1/3N cell.The battery contains enough power to print 133 photos. Thecharacteristics of the battery are listed in the following table.Parameter Value Type Designation CR1/3N Voltage (V) 3 ElectrochemicalSystem Lithium Typical Capacity (mAh) 170 Height (mm) 10.80 Diameter(mm) 11.60 Weight (g) 3.00

Throughout the specification the aim has been to describe the preferredembodiments of the invention without limiting the invention to any oneembodiment or specific collection of features. Persons skilled in therelevant art may realize variations from the specific embodiments thatwill nonetheless fall within the scope of the invention.

1. A compact printer comprising: at least one powered roller for movingprintable media past a fixed printhead; a nozzle capping mechanism forthe printhead, the nozzle capping mechanism having: at least one cappingarm operatively associated with the powered roller; a cap supported bysaid capping arm movable with said capping arm between a positionprotecting the printhead and a position spaced from said printhead; saidcap resting adjacent said printhead and the capping arm moving said capaway from said printhead when said powered roller rotates.
 2. Thecompact printer of claim 1 further comprising a clutch providing saidoperative association between said at least one capping arm and saidpowered roller.
 3. The compact printer of claim 2 wherein the clutch isa frictional clutch.
 4. The compact printer of claim 1 furthercomprising a motive means associated with said capping arm, said motivemeans moving said capping arm when said powered roller rotates.
 5. Thecompact printer of claim 4 wherein said motive means is a solenoid. 6.The compact printer of claim 4 wherein said motive means is a gearbetween said at least one powered roller and said capping arm.
 7. Thecompact printer of claim 1 wherein the cap comprises one or more sealsthat locate adjacent said printhead.
 8. The compact printer of claim 7where there is a single seal that locates either side around saidprinthead.
 9. The compact printer of claim 7 wherein said one or moreseals are elastomeric seals.
 10. The compact printer of claim 1 whereinsaid cap comprises one or more seals that locate adjacent said printheadand a blotter that locates near said printhead.
 11. The compact printerof claim 1 wherein there are two capping arms spaced apart to allowprintable media to pass between said two capping arms.